Adjustable slide bearing for motor grader moldboard supports



Aug. 26, 1969 I w, FlSHER 3,463,243

ADJUSTABLE SLIDE BEARING FOR MOTOR GRADER MOLDBOARD SUPPORTS Filed June 29, 1967 INVENTOR. WILLIAM F. FISHER United States Patent 3 463,243 ADJUSTABLE SLIDE BEARING FOR MOTOR GRADER MOLDBOARD SUPPORTS William F. Fisher, Decatur, 111., assignor to Caterpillar Tractor Co., Peoria, 111., a corporation of California Filed June 29, 1967, Ser. No. 650,011 Int. Cl. E02f 3/12; F16c 23/02, 25/02 US. Cl. 172-781 6 Claims ABSTRACT OF THE DISCLOSURE Background of the invention This invention relates to powered earthworking apparatus and more particularly to slide bearings for disposition between the side shift rails of a motor grader moldboard and the structure which couples the rails to the body of the motor grader.

In motor grader operations, productivity, job quality, and operating costs may each be adversely aifected by imprecision in controlling the position of the blade or moldboard. A factor which strongly influences grading precision is the amount of free play or looseness in the structure which attaches the blade to the body of the vehicle. Undesirable free play may result from the design of the blade supporting structure or from the wearing of elements which originally provided for fairly precise blade control. One area which is particularly troublesome in this respect is the coupling to the slide rails at the back of the blade.

Most motor graders have a draw bar carrying a rotatable blade circle at the underside of the frame, and the blade is supported through a pair of arms which extend downward from the blade circle. Brackets at the lower end of the arms engage the slide rails which extend along the back of the blade. Since means are usually provided for shifting the blade, in a direction parallel to the blade circle, a sliding coupling between the brackets and the rails is required. Because of the extremely large loading forces to which the blade may be subjected, wearing at this coupling occurs very rapidly and may be very pronounced.

Where the slide rails are of rectangular cross section, the mounting brackets are generally U-shaped to clasp the rails and a similarly shaped wearplate or slide bearing is disposed therebetween. As wearing occurs, it has heretofore been the practice to introduce shims from time to time to compensate for the increasing free play. However, access to the structure for the insertion of shims is inherently difiicult, and the operation is tedious and time consuming.

Summary of the invention This invention is a slide bearing for disposition between the blade rails and the blade supporting structure of a motor grader, the bearing being readily adjustable to compensate for wear so that a high degree of precision in blade positioning may be maintained. The bearing is formed by at least two separate members disposed against the associated rail within a bracket of the blade supporting structure and by adjustable means which bear against the members to determine the clearances between the members and the rail. In a preferred form, the component members of the bearing are right angled and one has a projection which extends into a matching recessed area of the other so that the two members are interleaved and jointly define a U-shaped bearing conforming to a rectangular rail.

Accordingly, it is an object of this invention to improve grading precision and to reduce the difliculty of maintenance operations in motor grader operations.

It is a further object of the invention to provide a slide rail bearing for the coupling between the blade and blade supporting structure of a motor grader which is more readily adjustable to maintain preferred clearances.

The invention, together with further objects and advantages thereof, will best be understood by reference to the following description of a preferred embodiment and by reference to the accomypanying drawings.

Brief description of the drawings In the accompanying drawings:

FIGURE 1 is a perspective view of the blade of a motor grader and showing the blade rails and blade supporting structure associated therewith;

FIGURE 2. is a cross section take along lines II-II of FIGURE 1 and showing the slide bearings of the present invention disposed between he blade rails and supporting structure; and

FIGURE 3 is an exploded perspective view of certain elements of the slide bearing of FIGURES 1 and 2 further clarifying the structure thereof.

Description of the preferred embodiments Referring now to the drawing and more particularly to FIGURE 1 thereof, the blade or moldboard 11 of a motor grader is normally supported by attachment to a blade circle 12 which has a pair of arms 13 that extend downward behind the blade. Sutable constructions for a blade circle 12 and structure for attaching the blade circle to the other components of the motor grader are well understood within the art.

Provision is usually made for side shifting or moving the blade 11 in a direction parallel to the plane of the blade circle 12 in a selective manner; and for this purpose, rails 14 extend along the back of the blade and are secured thereto. While slide rails are often welded to the back of a blade, imprecision can result in that distortions may occur as a result of the heating. In addition, the replacement of worn rails is very diflicult. To avoid these problems, this example of the invention utilizes an advantageous replaceable rail construction of a general type described more fully in co-pending application Ser. No. 606,228 of Russell D. Page, et a1. filed Dec. 30, 1966 and entitled Mechanism for Mounting a Side Shiftable Blade on a Motor Grader. In this construction, four rails 14 are used each being substantially shorter than the blade 11 with a first set of upper and lower rails 14 and 14, respectively, being disposed along a ,first half of the blade and a similar set of upper and lower rails being situated along the other half of the blade. Four mounting brackets 16 secure the rails to the blade with one bracket being disposed at each end of each set of upper and lower rails 14 and 14. Each bracket 16 has two apertures 17 which receive the ends of the associated rails 14 and 14' so that the rails are secured to the back of the blade in spaced relationship therefrom. In this example, the rails 14 and the apertures 17 of mounting brackets 16 are of square configuration.

Referring now to FIGURE 2 in conjunction with FIG- URE 1, a bracket assembly 18 at the lower end of each blade circle arm 13 engages the two sets of upper and lower rails 14 and 14' to support and position the blade 11. Each bracket assembly 18 has an arm 19 pivoted at the base to the lower end of the associated blade circle arm 13 at a shaft 21, so that the bracket assembly and blade 11 may be turned forwardly and rearwardly about shaft 21 to adjust the pitch of the blade relative to the blade circle. To fix the blade 11 at a selected degree of pitch, a slotted projection 22 extends rearwardly from the upper end of arm 19 and a bolt 23 is transpierced through the slot 24 and engaged in the blade circle arm 13. Thus, by tightening bolt 23, the upper end of bracket assembly arm 19 is clamped relative to the blade circle arm 13.

To provide powered means for selectively side shifting the blade 11, a double acting hydraulic jack 26 extends parallel to the blade between the two bracket assemblies 18. The barrel 27 of the jack 26 extends a short distance through an opening 28 at the central portion of each bracket assembly arm 19 and is secured therein, the extensible rod 29 of the jack being coupled to one of the end rail mounting brackets 16.

Considering now the coupling between rails 14 and bracket assembly 18, an inverted U-shaped bracket 31 is secured to the upper end of each bracket assembly arm 19 to form a passage 30 through which the upper rail 14 extends and a similar but reversed bracket 31' is secured to the lower end of the arm at the corresponding lower rail 14. The dimensions of the passage 30 of bracket 31 are greater than the cross sectional dimensions of the rail 14 to provide for the disposition of two bearing members 32 and 33 between each bracket and rail. The bearing members 32 and 33 at each bracket 31 jointly form a structure of U-shaped cross section generally conforming to the rail 14 and the bracket. However, unlike the brackets 31, the bearing defined by members 32 and 33 is compressible both vertically and horizontally to provide for adjusting clearances and to compensate for wear.

Referring now to FIGURES 2 and 3 in conjunction, each bearing member 32 associated with one of the upper rails 14 is right angled to form a first flat section 34 fitting against the rearward side of rail 14 and a second flat section 36 fitting against the upper surface of the rail. The central portion of the second section 36 has a rectangular slot 37 to receive a conforming projection 38 of the second bearing member 33. The second bearing member 33 has a flat rectangular section 39 fitting against the forward surface of the upper rail 14, and the projection 38 which extends into the slot 37 of member 32 is disposed at right angles to section 39 at the central portion of the upper edge thereof. Thus, when the two bearing members 32 and 33 are assembled with section 36 and projection 38 interleaved, a wearplate is formed which contacts three sides of the upper rail 14. Further, the bearing members 32 and 33 are moveable relative to each other in a fore and aft direction and also in a vertical direction to provide for adjustment.

Adjustment of the fore and aft clearance between the rail 14 and bearing members 32 and 33 is very readily effected by means of a pair of horizontally directed screws 41 engaged in the rear arm of the associated bracket 31 and bearing against the rear surface section 34 of bearing member 32 at spaced apart areas thereof. To adjust vertical clearances, a single vertically directed screw 42 is engaged in the central portion of bracket 31 to bear against the center of the upper surface of projection 38 of bracket member 33. To aid in holding a selected adjustment, both screws 41 and 42 may be provided with lock nuts 43.

The lower bearing members 32 and 33 are of similar construction but are reversed in position both vertically and in the fore and aft sense, as shown in FIGURE 2 in particular. Thus, bearing member 32 is adjacent the forward and bottom surfaces of the lower rail 14' while bearing member 33 fits against the back thereof and against the bottom surface. The horizontal adjusting screws 41 are engaged in the forward leg of the lower bracket 31' and no vertical adjustment screw is needed inasmuch as vertical clearance at both brackets may be fixed by adjustment of the upper screw 42.

Referring now again to FIGURE 1, the bearings are retained within the upper and lower brackets 31 and 31' by U-shaped end plates 44 which are secured to each end of each bracket by bolts 46.

While the invention has been disclosed with respect to a specific embodiment, it will be apparent that many modifications may be made.

What is claimed is:

1. In a bearing construction for supporting the blade of a motor grader in a slidable manner through a side shifting rail secured to said blade, the combination comprising:

a bracket carried by said motor grader and having a passage for receiving said rail; first and second bearing members disposed between said bracket and said rail in said passage, said bearing members being movable relative to each other in a direction normal to said rail, wherein said first bearing member has a slot therein receiving a projecting section of said second bearing member whereby said first and second bearing members have interleaved sections which are slidable relative to each other in said direction normal to said rail; and

means for adjusting the position of at least one of said bearing members relative to the other in said direction normal to said rail.

2. In a bearing construction for supporting the blade of a motor grader in a slidable manner through a side shifting rail secured to said blade, wherein said rail is of rectangular cross section, the combination comprising:

a bracket carried by said motor grader and having a passage for receiving said rail;

first and second bearing members disposed between said bracket and said rail in said passage, wherein said bearing members are right angled and have interleaved portions adjacent a single surface of said rail, said bearing members being movable relative to each other in a direction normal to said rail; and

means for adjusting the position of at least one of said bearing members relative to the other in said direction normal to said rail.

3. The combination defined in claim 2 wherein said first bearing member has a slot at a central region adjacent said surface of said rail and wherein said second bearing member has a projection entering said slot of said first bearing member, said slot and said projection being of matching rectangular configuration, and wherein said adjustment means comprises a first screw directed towards said projection and further comprises a pair of second screws directed against said first bearing member and spaced on opposite sides of said slot thereof, said second screws being normal to said first screw.

4. Slide bearing structure for engaging with a pair of vertically spaced upper and lower rectangular slide rails on a motor grader blade comprising:

an upper and a lower bracket carried by said motor grader, each having a rectangular passage through which a separate one of said rails extends; an upper and a lower bearing disposed between said upper and lower rails respectively and the associated one of said brackets, each bearing comprising first and second right angled bearing members disposed against the forward and rearward surfaces of the associated rail and having interleaved portions disposed against a third surface of said associated rail, said third surface being the upper surface of the upper rail and the lower surface of the lower rail;

means for adjusting the spacing of said first and second members of each bearing in a direction transverse to said rail; and

5 6 means for adjusting the vertical spacing of one of said References Cited bearings relative to the other thereof. UNITED STATES PATENTS 5. The combination defined in claim 4 wherein both 13553099 5 1913 McKnight 172 793 the fore and aft and vertical orientation of said members 2,258,890 10/1941 Gustafson 172-795 X of said lower bearing is reversed relative to that of said 5 2,581,602 1/ 1952 Pulsifel members Sald beanng' ROBERT E. PULFREY, Primary Examiner 6. The combination defined in claim 4 wherein said vertical adjusting means is a screw engaged in said upper bracket and bearing against said interleaved portions 10 us L of said upper bearing members. 308-3 STEPHEN C. PELLEGRINO, Assistant Examiner 

